Q: The tires on my 2007 Highlander have gone flat or at least lost enough air to set off the "flat tire" warning six times in the last four years. I've never had this happen on any other car, and I've been driving for over 50 years.
I take it in, and they say it's corrosion on the wheel and take care of it. It only happens in colder weather. The front tires were replaced seven years ago and have 45,000 miles on them.
The rear tires were replaced five years ago and have 31,000 miles. I keep my cars for at least 10 years, and this started happening when the tires were only two and four years old, respectively.
I don't know of anyone else having this problem and wonder if you have any insight. I have 88,000 miles on my car.
-- L.C., Park Ridge, Ill.
A: Corrosion is an industry-wide problem, particularly with alloy wheels. And it is especially common where they salt the roads. Buffing off the corrosion and applying a tire mounting compound are a couple solutions short of replacing the wheels.
Q: I have a 2016 Toyota Highlander (Limited Edition) and a fan that seems to be under the back seats often stays running hours after the car has been turned off. The only way I can turn it off is by starting the car and immediately turning it off again. The dealer says it's normal and it's clearing the exhaust system, but I say it's a problem that needs fixing. Any thoughts?
-- D.S., Lake Barrington, Ill.
A: About five hours after you park the vehicle, the evaporative emissions system (not the exhaust system) performs self-check for leaks. What you hear is a pump that pressurizes the system, which is then observed for a pressure drop, indicating a leak. Because most drivers park their cars overnight, this plan makes sense.
The test is interrupted by switching on the ignition or removing the gas cap, but I advise against that and suggest allowing the test to complete.